1. Field of the Invention
The present invention relates to a fuel quantity control apparatus of a supercharged diesel engine with safety measures.
2. Description of the Prior Art
In a supercharged diesel engine, the degree of supercharging is detected by the increase of the pressure in the air intake pipe, and the pressure in the air intake pipe is introduced into a boost compensator of a fuel injection pump to increase the amount of increase of the injected fuel quantity. The heat load of the diesel engine is increased by this increase of the fuel quantity and, hence, the wall temperature in the combustion chamber is elevated. If this temperature excessively elevates, however, it is liable to melt the combustion chamber wall or piston. Therefore, the above increase of the fuel quantity has to be stopped with a considerable safety margin and, hence, no satisfactory supercharging effect can be obtained.
When a turbocharger is used as the supercharging machine, the above-mentioned damage is liable to occur due to elevation of the temperature of the exhaust gas. Accordingly, the increase of the fuel quantity is controlled with considerable safety margin, and no satisfactory supercharging effect can be obtained. Reduction of the safety margin would increase the risk of the damage of the engine or turbocharger.